Rotary hook



nec 22 E6 G. A. soUTHAM Er AL 2,@655549 ROTARY HOOK Filed April 11, 1954Wzwimm A Panarea Der.. 22, 193e norAnY noon Gem-'ge A. sonumm ana Geomn. Wainwright.

Rockford, Ill., assignors to Free Sewin SMB.-

.\chine Co., Rockford, ll1.,a corporation of Illinoie ppucaupn April 11,1934, serial No. 719.9115 1s claims. (C1. i12-228)' 'I'he inventionrelates to an improved rotary hook construction for high-speed,lock-stitch type sewing machines and has as its general object toprovide a rotary hook of novel and improved con- 5 struction renderingthe hook more eillcient in operation and easier and more economical tomanufacture.

A more particular object of the invention is to facilitate and simplifymanufacture of the hook '10 by forming the thread guard thereon as anintegral part of the gib ring instead of as a part oi the thread-loopcarrier.

Another object is to mount the improved gib ring yieldahly on thethread-loop carrier to ob- 15 tain a oating gib ring rendering therotary hook less subject to becoming jammed and facilitating clearing ofthe hook.

`ii'et another object of the invention is to provide a yieldable orfloating gib ring and a beveled 2g rib on the bobbin case base with acorresponding beveled raceway formed by the gih ring and thread-loopcarrier to provide clearance on all sides oi the rib when the iioatinggib isl forced away from the thread-loop carrier. 2g Other objects andadvantages will become apparent from the following detailed descriptionI taken in connection with the accompanying drawing, in which:v l

Figure l is an edge elevational view of a ro- 3o tary hook embodying thefeatures of the invention. Fig. 2 is a 'front face elevational view oithe hooi: shown in Fig. l, with a portion of the gilo 40 modificationshowing the beveled rib and race-v way. v

' Fig. 6 is an enlarged fragmentary view sho another modified form ofbeveled rib and raceway. For purposes of disclosure, the scope of thein- 45 vention being dened by the appended claims,

the invention is shown in the drawing and will,

be described hereinafter as embodied in-a rotary hook comprisinggenerally a thread-loop carrier i supporting for relative rotationalmovement 50 a bobbin case base II whichin turn rotatably supports abobbin I2 retained in the base by acase I3. 'I'he thread-loop carrierIII has a hub Il by means of which it is secured to the driving l .shaftof a sewing machine (not shown) and a l 55 howl-shaped portion I5terminating in a radial flange I6. Received partially ywithin thebowlshaped portion I5 is the bobbin case base I I which is generallycylindrical and formed intermediate its ends with a circumferential ribi'l.- The rib II is received in Aan annular groove I1, shown 5 in Figs.3, 4 and 5 as formed in the inner periphery of the flange I6, and isretained in the grooveby a gib ring I8 secured to the ange I6 andforming with the groove I1 al raceway for the nb Hf. 1o

The bobbin case base I I is of conventional construction having a closedrear face Hb, spaced from the bowl-shaped portion I5 when the base ismounted in the thread-loop carrier, and an open front face. Projectingforwardly from the rear face l Ib and secured thereto centrally there--of is a pin i@ received within a tubular sleeve 2d of the bobbin casei3 when the latter is positioned within the base III to close the openface thereof. Extending radially from the base IIi is a recessed tongue2i which cooperates with a .it to maintain the proper tension on thebobbin thread. The rib il is cut away opposite the tongue 2l as 'shownin Fig. 2.

Projecting toward the front beyond the plane of the flange i6 is aloop-piercing tongue t5 and immediately forwardly of the tongue in. thedirection of rotation, the thread-loop carrier is formed with aconverging slot 2t extending radially inwardly obliquely to the axis ofthe hook in a direction counter to the rotation thereof. The tongue 25and the slot 26 operate in a well known manner to engage and spread thethreade loop formed by the downstroke of the needleof the machine,drawing one side ofthe loop with- 4o in the carrier through the cut awayportion of the rib Ha to pass the loop on opposite sides of the bobbincase base i I and thus lock the stitch.

Heretofore the slot 26 was closed'at the periphery of the thread-loopcarrier by a portion. of the nange I6 which continued across the slot toform a thread guard. To facilitate manufacture of the hook, the threadguard is formedhereirr as air-integral part of the gib ring I8 thuspermitting the slot 26 to be open at the periphery of 50 the thread-loopcarrier which materially `facilitates the formation thereof. Hereinthegib ring I8 is shown as a split ring positioned with one end terminatingapproximately at the forwardedge of theslot 26 and havinga finger 21 atthe 55 Vinstead of in the thread-loop carrier.

other end extending across the loop-piercing tongue and the slot 26 toform the thread guard. The gib ring is secured to the flange I6 by meansof circmferentially spaced screws 28 and is formed with a second flnger28 conforming in contour to the rear edge of the tongue 25 and with itsouter edge flush with the edge of the tongue (see Fig. 1) to provide asmooth uninterrupted transition from the ring to the tongue.

A construction is employed which minimizes the possibility of locking orjamming of the hook by the presence of foreign matter in the racewayformed by the groove I1 and the gib ring and facilitates clearing thehook should it become jammed. To that end the gib ring I8 is floatinglymounted, that is, having a limited lateral movement. Herein suchfloating or yieldable mounting of the gib ring is obtained by the use ofcoiled compression springs 30 encircling the screws 28 and interposedbetween the heads thereof and the flange IB, the thread-loop carrier Ibeing formed with recesses 3l to receive the springs. At the inner endeach recess 3I is formed with a shoulder 32 against whichthe spring 30abuts and which slidably engages the screw projecting therethrough toform a guide means for the lateral movement of the gib ring. The threadson the screws 28, as conventionally shown in the drawing, permit thescrews to be turned in only a fixed distance and thus assure uniformcompression of all of the springs. In Figs. 3 and 4 the rib II on thebobbin case base and the raceway in which it is received arerectangular. It will be apparent from the foregoing description thatshou1d foreign matter enter the raceway, the gib ring I8 is free toyield laterally thus enabling the bobbin case base to rotate relative tothe threadloop carrier in spite of the foreign matter, with thepossibility that the hookwill eventually clear itself of the foreignmatter, or the gib ring may be conveniently moved manually to facilitateremoval of the foreign matter from the raceway by;I

the operator of the machine.

Figs. 5 and 6 show modified forms of the construction of the raceway andthe rib IIa on the bobbin case base enabling the hook to clear itselfeven more readily or to facilitate to a greater extent the removal offoreign matter by the operator of the machine. In the modifled forms therib on the bobbin case-base is no longerrectangular but has a beveledperipheral surface. The raceway formed by the gib ring and thethread-loop carrier is correspondingly beveled. In Fig. 5 the beveledsurface 33 faces toward the rear of the hook and the thread-loop carrieris formed with an annular groove 34 having a beveled surface 35 tocorrespond to the beveled surface 33 of the rib IIe. 'Ihe gib ring is ofthe same construction as that in Figs. 1 to 4.

In Fig. 6 the gib ring I8 is substantially thicker than that shown inthe other figures and a groove 36 for receiving the rib II@- is formedtherein The groove has a beveled surface 3'Il to correspond to thebeveled surface 33' on the rib II which is however, formed to facetoward the front of the rotary hook. The screws 28 are also reversedfrom the position 'shown in the remaining figures and are threaded intothe thread' loop carrier with the springs 30 concealed in recesses 3lformed in the gib ring.

It will be apparent that with the peripheral surface of the rib IIabeveled, movement of the floating gib ring laterally not only providesclearance along the radial faces of the rib IIa but also at the beveledface of the rib. Thus a clearance is 'provided between each of the facesof the rib and the raceway, thus rendering it almost impossible forforeign matter in the raceway to prevent relative rotation of thethread-loop carrier and the bobbin case base.

We claim as our invention:

1. In a rotary hook for sewing machines. a rotary thread-loop carrierhaving a loop-piercing tongue, a bobbin case base having acircumferential rib, and a gib ring secured to said carrier and formingtherewith a raceway for the rib on .said base, said ring having a threadguard integral therewith and at least a part of the thread guarddisposed forwardly of said loop-piercing tongue considered in thedirection of rotation.

2. In a rotary hook for sewing machines, a rotary thread-loop carrierhaving a slot extending inwardly from the periphery thereof obliquely tothe axis of said carrier to form a loop spreading tongue, a bobbin casebase having a circumferential rib, and a gib ring secured to saidcarrier and forming therewith a raceway for the rib on said base, saidring having a thread guard integral therewith and extending across theloop spreading tongue and the slot.

3. In a rotary hook for sewing machines, a bowl-shaped rotarythread-loop carrier having a radial flange at its periphery and a. slotextending inwardly from the periphery obliquely to the axis of the hookand counter to the direction of rotation to form a thread-loop spreadingtongue, a bobbin case base partially received within said carrier andhaving a circumferential rib, and a split gib ring secured to saidcarrier and forming with the flange thereon a raceway for the rib onsaid base, said ring having a finger extension at one end projectingacross the slot to form a thread guard.

4. In a rotary hook for sewing machines, a rotary thread-loop carrier,'a bobbin base having a circumferential rib, a gib ring disposed on theoutside of said carrier and forming therewith the entire raceway for therib on said bobbin case base, and means for yieldably mounting andguiding said gib ring on said carrier for limited lateral movement.

5. In a rotary hook for sewing machines, a`

rotary thread-loop carrier, a bobbin case base having a circumferentialrib, a gib ring disposed opposite said carrier and forming therewith asubstantially 360 raceway for the rib on said base, and means foryieldably mounting said ring on said carrier for limited lateralmovement comprising circumferentially spaced screws and compressionsprings encircling the same, said screws also serving to guide said ringin its lateral yielding movement.'

6. In a rotary hook for sewing machines, a bowl-shaped rotarythread-loop carrier having a slot extending inwardly from the peripherythereof obliquely to the axis of the hook to form a loop spreadingtongue, a bobbin case base partially received within said carrier andhaving a circumferential rib, a gib ring disposed opposite said carrierand forming therewith a raceway for the rib on said base, said ringhaving a portion extending across the slot in said carrier to form athread guard and means for yieldably mounting and guiding said ring forlimited lateral movement.

'1. In a rotary hook for sewing machines, a bowlshaped rotarythread-loop carrier having a radial flange at its periphery and anannular groove formed in the flange, a bobbin case base having acircumferential rib, a gib ring disposed opposite the ange on saidcarrier and forming with the groove therein a raceway for the rib onsaid base, circumferentially spaced recesses formed in the. iiange ofsaid thread-loop carrier, an annular shoulder in each recess, a screwextending through each recess and threaded into saidV gib ring, and acoiled compression spring encircling said screw and abutting the headthereof and the shoulder in said recess to hold said gib ring yieldablyagainst the ange of said thread loop carrier.

8. In a rotary hook for sewing machines, a rotary thread-loop carrier, abobbin case base having a circumferential rib with a beveled pe ripheralsurface, a gib ring disposed opposite said carrier and forming therewitha raceway having a beveled surface corresponding to the` rib on saidbase, and means for yieldably mounting said ring on said carrier.

9. In a rotary hook for sewing machines, a rotary thread-loop carriermember, a bobbin case base having a circumferential rib with itsperipheral surface beveled, a retaining ring member disposedl oppositesaid carrier member, one of said members having an annular groove with abeveled surface corresponding to the beveled sur.

face of the rib on said base and forming with the other `member araceway for the rib, and means' for yieldably mounting said retainingmember on said carrier member.

10. In a rotary hook for sewing machines, a`

' hook, a gib ring disposed opposite said `carrier and having an annulargroove beveled to conform to the rib on said base and forming with thecarrier a raceway for the rib, and means for yieldably mounting saidring on said carrier.

ll. In a rotary hook forpsewing machines, a rotary thread-loop carrier,a bobbin case base having a circumferential rib with a beveled perotarythread-loop carrier, a bobbin case base having a circumferential ribwith a beveled peripheral surface, `a gib ring disposed opposite said'carrier and having an annular groove beveled to conform to the rib onsaid base and forming with the carrier a raceway for the rib,circumferentially spaced recesses formed in said ring, a shoulder ineach recess, a screw projecting through each recess and threaded intosaid carrier, and a compression spring interposed between the head ofthe screw .and the shoulder in the recess.

13. In a rotary hook for sewing machines, a bowl-shaped rotarythread-loop carrier having a radial ange at its periphery, a bobbin casebase received within the carrier having a circumferential rib with abeveled peripheral surface facing the carrier", said carrier having anannui-l lar complementary beveled groove in which the rib of said baseis received, a gib ring disposed opposite the flange on said'carrler andforming with the groove therein a raceway for the rib on said base,`circurnferentially spaced recesses formed in the ange of saidthread-loop carrier, an annular shoulder in each recess, a screwextending through 'each recess and threaded into said gib ring, and acoiled compression spring encircling said screw and abutting the headthereof

